The present invention relates to a vacuum treatment system with at least one vacuum treatment chamber, wherein a first part of the system is connected with an electrical system reference potential—by convention ground potential; in the vacuum chamber a further part is provided to which is applied an electric potential varying by at least ±12 V from the system reference potential, and wherein at this further part at least one sensor and/or at least one adjusting element is disposed, further with an electronics unit which is operatively connected at the input and/output side with the sensor and/or adjusting element.
Such a prior known vacuum treatment system is depicted schematically in FIG. 1 as an example with a path of plasma discharge and will be discussed in conjunction with this figure. In the vacuum chamber 1 a plasma discharge path is provided in this example between electrodes 3a and 3b. The discharge path denoted by 3 is operated electrically by a supply unit 5, with this being either DC, pulsed DC, with AC or with AC and superimposed DC, wherein the AC signal frequency can be in the Hz up to the high frequency, for example even in the microwave range.
For the purpose of explanation, in FIG. 1 the electrical supply leads to the discharge path 3 from the chamber 1 are shown as being electrically insulated. Different ways exist of superimposing the system reference potential, by convention ground potential φ0. This is schematically shown by the option selection switch 7. It is conventional, for example, to put the housing 1 as well as one of the electrodes 3a, 3b at ground. In the vacuum chamber 1 a further part 9 is depicted, for example a substrate support, an instrument support, a further electrode etc., wherein this part 9, shown separately for the purpose of the explanation, can also be one of the electrodes 3a, 3b. This part 9 is now not at potential φ0. This is shown with the unit 4 according to an impedance and/or source equivalent circuit diagram.